Silicon oxide has approximately the same optical properties as quartz glass, i.e. is transparent in the visible spectrum range. In practice, in order to manufacture transparent regions in connection with a silicon substrate, silicon oxide layers are deposited on the silicon substrate which are subsequently structured.
However, the conventional method is problematical from several points of view. For example, using the conventional method, only optically transparent regions having a small layer thickness can be generated. Besides that, the manufacturing of such an optically transparent region over a cavity in the silicon substrate cannot be done in a simple manner, so that the optically transparent regions made within the framework of the conventional method, as a rule, cannot be used as an optically transparent cover for a cavity or fluid channel, as are needed, for example, for optical investigations on the smallest quantities of fluids in medicine or in analytical work.